What are the effects of Proteins, Fats, Carbs and Fibre?

Proteins, fats, and carbs are the three macro-nutrients, with fibre debatably a fourth (but technically a micro-nutrient). These all have their own roles in a diet and will have different effects on your body and the way you feel.

Starting with protein, this is a necessary macro-nutrient for the maintenance and growth of muscle tissue. However, it is also hugely important to focus on when trying to lose weight as it is the most satiating of all food types. It will take a long time for you to digest protein, meaning it will keep you full for longer. Furthermore, because it is difficult for your body to break down protein, it takes more energy (calories). This is known as the thermic effect of food – basically, you burn off more calories to digest protein than you do with fats or carbs.

Carbohydrates are the macro-nutrient which fuel your body with readily available energy and therefore support day-to-day activity, and intense exercise also. Although these are not vital for our survival, the majority of people should be prioritising getting an adequate intake.
When it comes to dieting, the effects of carbohydrates can be both good and bad. When your energy is low, a higher carbohydrate intake can help reduce the negative effects of the diet and help you to maintain performance. Also, they will supply you with more energy, making you more likely to move around during the day, subconsciously burning more calories.
However, carbohydrate intake will cause a spike in insulin levels more so than any other macro-nutrient. This doesn’t directly cause weight or fat gain itself, however, it can lead to increased hunger throughout the day which if not controlled, will lead to eating more throughout the day – potentially leading to weight gain.

Fats are a vital macro-nutrient and will have the most noticeable effects on your body, mood, and everything else. They support hormone production in your body and therefore have a massive impact on your mood, energy, mental clarity, etc. Along with hormone support, fats are another highly satiating macro-nutrient – just like protein intake. They provide a longer lasting, slow release form of energy than carbohydrates do, meaning they will help you to stay full for longer, making fat intake very beneficial when trying to diet and lose weight. In terms of calorie density, not all foods are the same. Every gram of carbohydrate contains 4 calories, which is the same for each gram of protein. Fat however contains 9 calories per gram. This does not mean that fat is worse for you, and as mentioned above, can be a fantastic appetite suppressant when dieting. You just need to be careful not to go overboard on your fat intake.

When considering the effects of proteins, fats, and carbs on your energy levels, you can think of them as paper, logs and coal.
Carbohydrates are your paper – they burn up quickly but don’t last very long.
Fats are your logs – they are readily available for energy, however, take a longer time to burn up and last much longer.
Protein is your coal – a slow burner which will be used for a long time and forms the base of your energy.


This was just one of the questions covered in our latest “Let’s Talk: Nutrition” talk with Ash. Keep your eyes peeled for our next talk and if you have any questions feel free to grab Ash in the gym.